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Test if lists share any items in python
... generally the fastest.
There are four common ways to test if two lists a and b share any items. The first option is to convert both to sets and check their intersection, as such:
bool(set(a) & set(b))
Because sets are stored using a hash table in Python, searching them is O(1) (see here for...
What do the plus and minus signs mean in Objective-C next to a method?
In Objective-C, I would like to know what the + and - signs next to a method definition mean.
4 Answers
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Printing a variable memory address in swift
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Swift 2
This is now part of the standard library: unsafeAddressOf.
/// Return an UnsafePointer to the storage used for `object`. There's
/// not much you can do with this other than use it to identify the
/// object
Swift 3
For Swift 3, use withUnsafeP...
Combining two expressions (Expression)
I have two expressions of type Expression<Func<T, bool>> and I want to take to OR, AND or NOT of these and get a new expression of the same type
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Why does (0 < 5 < 3) return true?
I was playing around in jsfiddle.net and I'm curious as to why this returns true?
14 Answers
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What is the difference between CHARACTER VARYING and VARCHAR in PostgreSQL?
...rchar, so no difference, see documentation :)
The notations varchar(n) and char(n)
are aliases for character varying(n)
and character(n), respectively.
character without length specifier is
equivalent to character(1). If
character varying is used without
length specifier, the type ac...
What is Compass, what is sass…how do they differ?
I would like to start using compass and sass to speed up development. At the moment, I have installed Sass on a mac and instructed it to watch scss file for input, and a css file for generated output.
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Python if-else short-hand [duplicate]
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The most readable way is
x = 10 if a > b else 11
but you can use and and or, too:
x = a > b and 10 or 11
The "Zen of Python" says that "readability counts", though, so go for the first way.
Also, the and-or trick will fail if you put a variable instead of 10 and it evaluates to Fals...
How to set xlim and ylim for a subplot in matplotlib [duplicate]
I would like to limit the X and Y axis in matplotlib but for a speific subplot. As I can see
subplot figure itself doesn't have any axis property. I want for example to change only the limits for the second plot!
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mongodb, replicates and error: { “$err” : “not master and slaveOk=f...
mongodb, replicates and error: { “$err” : “not master and slaveOk=false”, “code” : 13435出现这个错误的原因是在从库上执行命令导致，默认情况下只有主库可以执行命令。当然可以通过设置使得从库也能执行命令，具体参见：http: s 出现...